1. Field of the Invention
The present invention relates to a toner for forming a toner image in image-forming methods such as electrophotography and electrostatic printing or in toner jet-based image-forming methods.
2. Description of the Related Art
Investigations in pursuit of improvements in the tribocharging characteristics of toners are being actively carried out. In particular, the use of a resin having a charge control function (a charge control resin) as a toner starting material has been proposed in recent years based on considerations such as environmental concerns, demands for a more stable charging performance, production costs, and so forth. For example, toner in which a resin containing sulfonic acid is used as the charge control resin has been proposed (Japanese Patent Application Laid-open No. H11-327208 and Japanese Patent No. 2,807,795). According to this proposal, it is possible to obtain toner having stable charging characteristics with little variation in the charge amount due to the environmental variations.